Britain voted to leave the EU,

a new prime minister is ready to make that happen

but nobody is quite sure what it means.

No talks have started,

and Britain is still a full EU member.

But politically,

everything has changed.

The UK and the EU,

are parting ways after 43 years.

The question is

when

and how?

There are stages to this divorce.

The first, is on the British side.

With Theresa May taking office to succeed David Cameron as prime minister,

the UK has a new leader.

What it needs now is a plan.

Mrs. May will barely have moved into Downing Street,

before she'll face pressure to reveal her Brexit strategy.

Her debut on the world stage will be at the September 4th summit, of G20 leaders in China.

A better moment to set out her views on Brexit,

may be Britain's Conservative Party Conference on October 2nd.

Shortly after that,

on October 20th,

she will attend her first EU summit in Brussels.

It will be a strange welcome.

For Europe will be in the second stage of Brexit,

setting the terms of engagement.

The EU 27 are refusing to talk until Britain invokes article 50,

the formal exit clause in the EU treaty.

That would give the EU side

the whip hand,

by starting the clock on the two-year Brexit deadline,

which only the EU can extend.

There may be an Article 50 standoff,

it is not just controversial in Brussels,

but Westminster too.

Ultimately though,

most senior conservatives accept it should be triggered at some point.

Mrs. May has mentioned the new year,

so Brexit day could well be January 1st, 2019.

Sorting that breakup is a third stage.

This divorce severs ties and settles old obligations and rights

like budget dues and the status of expats.

What this doesn't involve

is the future UK-EU relationship.

That is the fourth stage of Brexit,

and may take longer.

The divorce does take account of what comes next.

So the two sides may agree on a common goal,

say, a Canada style trade deal,

or a deep Norway style single market relationship.

But the details will be agreed after divorce.

Settling them and ratifying a trade deal in 38 national and regional parliaments could take five years or more.

That means a transition will be needed to avoid hard Brexit,

where Britain leaves without a trade deal.

As you can see,

Brexit is a complex business

even if all goes to plan.

There is every chance it could turn hostile and ugly,

and a lot rides on Britain.

What Brexit does it want?

And will voters change their mind?

Campaigners for Britain to leave the EU made the country's businesses some big promises.

An escape from burdens and European red tape,

access to new trading opportunities around the world.

Is this what Brexit really offers, business?